Micro-image display apparatus



Jan. 28, 1969 HIDEO AKIYAMA ET AL MICRO- IMAGE DI SPLAY APPARATUS FiledMay 51, 1966 Sheet INVENTORS HIDEO AKIYAMA DAVID G. STOCKWELL O/QMQ 4. mBY 0; i

THEIR ATTORNEYS Jan. 28, 1969 HIDEO AKIYAMA ET AL 3,424,524

MICRO-IMAGE DISPLAY APPARATUS Sheet Filed May 31, 1966 FIG.5

INVENTORS u 2 m s W m A W v! R M K O A m a 0/ T Y I T T K S A A G m OD17E m M d T H D Y 2.... B m b m .1 I l w f 8 l Jan. 28-, 1969 HIDEOA'KIYAMA ET 3,424,524

MICRO-IMAGE DISPLAY APPARATUS Filed May 31, 1966 Sheet 5 of :5

INVENTORS HIDEO AKIYAMA DAVID G. STOCKWELL BYogdzmyfi diva 2% a THE IRATTORNEYS United States Patent 14 Claims This invention relatesgenerally to means and methods for retrieving data recorded inmicro-image form, and more particularly to means for displayingmicro-images.

The broad object of this invention is to provide improvements inmicro-image display means.

A more specific object is to provide simple and economical means fordisplaying, from a transparency, a selected one of a large plurality ofhigh resolution microirnages of 100 to 1 or greater reduction ratio.

Another object of this invention, in accordance with the previousobject, is to provide micro-image display means including greatlysimplified and novel means for accurately maintaining the required smallworking distance between the projection lens and the transparency as thetwo are relatively moved so as to permit a desired micro-image to bedisplayed.

A further object of this invention, in accordance with one or more ofthe foregoing objects, is to provide a micro-image display means havingimproved means for inserting and removing a transparency containing alarge plurality of micro-images.

The manner in which the above objects are accomplished in accordancewith the invention, as well as other objects, advantages and featuresthereof, will become apparent from the following description and theaccompanying drawings in which:

FIG. 1 is a view of a transparency containing a plurality ofmicro-images, any selected one of which can be displayed in accordancewith the invention.

FIG. 2 is a pictorial view, partially broken away, of a micro-imagedisplay apparatus incorporating the invention.

FIG. 3 is a cross-sectional side view of FIG. 2 taken along the line 33and showing the apparatus in position to receive a transparency.

FIG. 4 is a fragmentary, partially schematic view of FIG. 1 showing themajor components of the apparatus.

FIG, 5 is an enlarged partial view of FIG. 3 showing details of theprojection lens and the glass supporting member holding thetransparency.

Like characters designate like elements throughout the figures of thedrawings.

In the specific embodiment of the invention to be described herein, amicro-image may, for example, be an image of about .8" X .10" having aresolution of typically 500 lines per millimeter, which is to bedisplayed at a magnification of typically 100 to 1 or greater. Withreference to FIG. 1, the term transparency refers to a thin flexibletransparent film having a large plurality of micro-images 11 recordedthereon. The transparency 10 may typically comprise a 0.3 millimeterthick 3" x 5'' rec tangular cellulose film having over 1,000micro-images 11 recorded thereon in a row-column arrangement. The wordsWorking distance will be used herein to designate the spacing betweenthe transparency and the nearest element of the micro-image displaymeans.

A preferred embodiment of a micro-image display means in accordance withthe invention is illustrated in FIGS. 2-5. This preferred embodiment isof the rear projection type which projects a selected micro-image 11(FIGS. 2 and 4) recorded on a transparency 10 inserted in the apparatus,via a projection lens assembly 35, mirrors 21 and 22, and oscillatinganti-scintillation screen 23 3,424,524 Patented Jan. 28, 1969 (FIGS. 3and 4), onto the back of a translucent viewing screen 25 for viewingfrom the front thereof.

It will be understood that during display of a selected micro-image 11recorded on a transparency 10, the transparency 10 is caused to befirmly held flat and horizontal (FIGS. 2, 4 and 5) between upper andlower glass plates 12 and 15 which, in turn, are disposed in a slidableglass support member 18 having tetrafluorethylene (commonly known by thetrade name Teflon) coated legs 18a. so as to permit smooth slidingmovement of member 18 on horizontal base 19 under projection lensassembly 35. Also provided is a position control bar 20 havingtetrafluorethylene coated legs 20a for smooth sliding movement on base19, and tetrafluoroethylene coated edges 20b (FIGS. 2 and 4) for smoothsliding movement between end flanges 19a provided on base 19, wherebyposition control bar 20 is restricted to slidable movement on base 19 inthe direction of arrow In order to control the x-y position of glasssupporting member 18 with respect to projection lens assembly 35,position control bar 20 is additionally provided with an engaging member20b (FIG. 5) cooperatively coupled to an engaging member 18b of glasssupport member 18 so .as to permit member 18 to move together with bar20 for movement in the direction indicated by arrow y, while alsopermitting member 18 to slide along bar 20 so as to provide movementthereof in the direction indicated by arrow x (FIGS. 2 and 4). The xposition of the transparency 10 in glass supporting member 18 isindicated by a scale 200 provided on position control bar 20, and the 1position of the transparency 10 in glass supporting member 18 isindicated by a scale 1917 provided on one of the base flanges 19a,whereby each micro-image 11 on a transparency 14 can be locatedrespective x-y coordinates on scales 20c and 19b.

In order to permit simple and expeditious insertion of the transparency10 between glass plates 12 and 15, the glass cover plate 15 has its backend suitably aflixed to a pivot member 15a (FIGS. 3-5) which ispivotable about rod 15b suitably attached to glass support member 18. Aswill hereinafter be explained in more detail, the projection lensassembly 35 (FIGS. 3 and 5) is urged against the upper glass plate 15 inorder to maintain focus for any x-y position of the transparency. In thepresent invention, such urging is also advantageously used for theadditional purpose of providing the force required for pivoting theupper glass plate 15 upward into a transparency receiving position (FIG.3). This is accomplished by simply moving frontward control bar 20 (andthus glass support member 18) until the projection lens assembly 35 ison the back side of pivot rod 15b, as shown in FIG. 3. An additionaladvantage is that there is no need to provide for lifting of theprojection lens assembly 35 in order to insert a transparency 10.

To facilitate proper alignment of a transparency 10 inserted betweenglass plates 12 and 15, the glass support member 18 is provided with asloping receiving surface 18c and guide flanges 18d forming grooves 18c(FIG. 3) between which the side edges of the transparency are inserted.The lower glass plate 12 is disposed below guide flanges 18d in a cutout recess 18 (FIG. 5) of glass support member 18 so as to provide aslightly raised shoulder 18g (FIGS. 3 and 5) for stopping the leadingedge of an inserted transparency 10 in a properly aligned position.

Having described how the spring biasing of the projection lens assembly35 against the upper glass plate 15 provides for insertion of atransparency in proper alignment between glass plates 12 and 15 of glasssupport member 18, and how an inserted transparency 10 can be positionedto a desired x-y location with the aid of the position control bar 20coupled to glass support member 18, the optical and associated portionsof the display apparatus will next be considered.

Referring to FIGS. 3 and 4, it will be understood that the basic lightsource for the display apparatus is provided by a light condensingassembly 40 disposed in a suitable enclosure 50 (FIGS. 2 and'3) below anillumination hole 190 (FIGS. 3-5) provided in base 19 opposite theprojection lens assembly 35, the base 19 serving as a top cover for theenclosure 50. The light condensing assembly 40 includes a filament-typelamp 40a energized from an A-C power source via a plug 51 and anappropriate transformer 52 (FIG. 4), cooling fins 40b (FIGS. 3 and 4),and a focusing lens and heat filter 40c. A fan 60 (FIGS. 3 and 4) isprovided at the rear of the apparatus for cooling purposes. The back end50a (FIG. 3) of enclosure 50 is open to receive cooling air from fan 60,which flows past light condensing assembly 40 and out of slots 50b(FIGS. 1 and 3) at the front end of the enclosure 50.

As will be understood from FIGS. 3 and 5, the focusing lens 40c providesa beam of light which passes, via hole 19c, to form a reduced focusedimage of the filament of lamp 40a on the transparency 10 held betweenglass plates 12 and 15, the transparency area illuminated beingsufficient to include at least one micro-image 11, and may typicallyinclude many micro-images. The glass plates-12 and 15 aid in preventingoverheating of the transparency by conducting heat away therefrom.

Light passing through the selected micro-image on the transparency 10 iscollected by a projection lens 30 contained in the projection lensassembly 35 (FIGS. 3 and causing an enlarged image of the selectedmicro-image to be focused onto the viewing screen 25, via mirrors 21 and22 and oscillating anti-scintillation screen 23 (FIGS. 3 and 4)contained in an upper enclosure 47 (FIGS. 2 and 3). Anti-scintillationscreen 23 is driven for movement between pins 29 (FIG. 4) and viewingscreen 25 by motor 28, which is chain-coupled to driving shafts 26 and27 having respective cams 26a and 27a respectively cooperating withlower edge member 23a (FIGS. 3 and 4) and hole 23b (FIG. 4) at thebottom of screen 23. Slidable hood 48 (FIGS. 2 and 3) is provided overthe upper enclosure 47 to screen out extraneous light.

It will be understood that projection lens 30 (FIGS. 3 and 5) is amicroscope type lens corrected for cover glass plate 15 and typicallyhaving a magnification of 115, a numerical aperture greater than 0.3,and a very small working distance (i.e. the distance between the nearestelement of the lens 30 and the transparency which is typically less than20 millimeters and may, for example, be 11 millimeters. It will also beunderstood that such a lens 30 is provided with a very limited depth offocus in order that scratches on the transparency surfaces (also on thesurfaces of the glass plates 12 and will be out of focus, and therebynot interfere with the quality of the micro-image displayed on theviewing screen 25. Such a situation produces a problem for a micro-imagedisplay apparatus, because of the importance of maintaining themicro-images on the transparency substantially in focus for any x-yposition to which the transparency is moved. Instead of providing anexpensive recise x'y positioning mechanism to solve this problem, thepresent invention causes the projection assembly to be urged againstcover glass plate 15 which is chosen to be of precise uniform thicknessof typically 0.125 inchix002 inch, whereby the working distance willremain substantially constant despite changes in the actual horizontalposition of the transparency caused by an imprecise x-y movement.

The upper surface of glass cover plate 15 is provided with a thinanti-reflection coating 15c (FIGS. 3 and 5). It might be thought thatthe urging of the projection lens assembly 35 thereagainst would causescratching or galling of the coating 15c during x-y movement, andthereby require lifting of the lens assembly 35 off the cover glassplate during x-y movement. However, by providing the lens assemblyportion 37 which contacts the upper glass plate 15 with a lubricatingsurface 37a (FIG. 5), such as provided by a film of .002 to .005 inchtetrafluorethylene, and with five pounds of urging pressure, the coverglass plate 15 was found to be free of scratches or galling even afteras many as ten thousand strokes of approximately two seconds per stroke,and wear on the tetrafluorethylene surface was only about .0005 inch.Thus, in accordance with the present invention, the projection lensassembly 35 need not be lifted from the cover glass plate 15 during xymovement, nor for insertion of a transparency as previously explained inconnection with FIG. 3.

Referring primarily to FIG. 5, the projection lens assembly 35containing the microscope-type projection lens 30 will now be consideredin detail. The fixed portion of the lens assembly 35 is a hollow tubularmember 32 affixed to a support member 47a of the upper enclosure byflanges 32a provided at the upper end of member 32. Member 32 is open atits lower end, and at its upper end is provided with a reduced diameterhole 32b concentric with a hole 47b in support member 47a leading tomirror 21. A biasing spring 31 is inserted in fixed tubular member 32from the lower end threof, followed by a slidable cylinder 33 in whichthe prejection lens 30 is secured by a set screw 34. The slidablecylinder 33 has a reduced diameter portion 33a cooperating with a setscrew 33b to restrict the vertically slidable movement of cylinder 33 tothe length of the reduced portion 3311.

Still referring primarily to FIG. 5, projection lens 30 is provided witha reduced threaded portion 30a on which is threaded a groovedcylindrical focus adjusting member 36 (see also FIGS. 2 and 4) having asufficient inner diameter to receive fixed tubular member 32.Cylindrical member 36 also has a reduced diameter portion 37 at itslower end, which is coated with a lubricating film 37a, such astetrafiuorethylene or molybdenum disulfide. The spring 31 is chosen sothat the projection lens assembly 35 is urged against the cover glassplate 15 via lubricating film 37a for all xy positions of thetransparency 10. It will be understood that by manually adjusting focusmember 36 on the threaded portion 30a, the working distance is varied,thereby providing a convenient manual focusing control, which focusingwill be maintained by the spring biasing regardless of the xy positionof the transparency. Although gravity alone could be used for urging theprojection lens assembly 35 against glass plate 15, it is much moreadvantageous to use spring biasing since the urging pressure can beconveniently controlled independently of the weight of the projectionlens assembly 35.

Although the description herein has been concerned with a particularillustrative embodiment, it is to be understood that the invention issubject to various modifications in both construction and arrangementwithout departing from the spirit of the invention. The invention,therefore, should be considered as including all possible modificationsand variations coming within the scope of the invention as defined inthe appended claims.

What is claimed is:

1. In apparatus for displaying a reduced image recorded on atransparency, a projection lens assembly, a light source, retainingmeans for retaining a transparency between said projection lens assemblyand said light source, said retaining means including a pivotable memberdisposed over and in contact with the transparency on the projectionlens assembly side thereof, means for urging said projection lensassembly against said pivotable member, and means for moving saidretaining means to a position so that the urging of said projection lensassembly against said pivotable member causes pivoting thereof, wherebya transparency can be inserted or removed.

2. The invention in accordance with claim 1, wherein said pivotablemember includes a cover glass plate, and wherein the portions of saidprojection lens assembly which contact said pivotable member areprovided with a lubricating film.

3. The invention in accordance with claim 1, wherein said projectionlens assembly contains a microscope-type projection lens providing amagnification of 100 to 1 or greater and having a working distance ofless than 20 millimeters.

4. The invention in accordance with claim 3, wherein said projectionlens has a numerical aperture of 0.3 or greater.

5. In apparatus for displaying a selected reduced image from atransparency containing a large plurality of reduced images recordedthereon, a projection lens assembly, a light source, first means forretaining a transparency between said lens and said light source, secondmeans cooperating with said first means for positioning a selected imagein a display position with respect to said projection lens assembly,said first means including a reference member providing a surfaceparallel to and precisely spaced from the transparency and beingtransparent for those portions thereof adjacent said reduced images, andmeans for resiliently urging said projection lens assembly against saidreference surface for all image display positions of the transparency,whereby said lens assembly is maintained at a precise distance from saidtransparency for all image display positions thereof.

6. The invention in accordance with claim 5, wherein said referencemember includes a cover glass plate disposed over and in contact withsaid transparency, and wherein the portions of said lens assembly whichcontact said reference member are provided with a lubricating film,whereby movement of said first means is obtainable without lifting saidprojection lens assembly from contact with said reference member.

7. The invention in accordance with claim 5, wherein said referencemember is pivotably mounted at one end thereof, and wherein said secondmeans is constructed and arranged to permit said first means to be movedto a position such that the urging of said projection lens assemblyagainst said reference member causes pivoting thereof, whereby atransparency can be inserted or removed without raising said projectionlens assembly.

8. Micro-image display apparatus for displaying a selected one of alarge plurality of micro-images recorded on a transparency comprising: aviewing screen, a light source, first means for receiving a transparencyand for retaining the transparency in a position so as to receive lightfrom said light source, a projection lens assembly having a projectionlens located so as to receive light from said source after passingthrough said transparency, second means for positioning a selectedmicro-image in a display position with respect to said projection lens,means cooperating with said projection lens so as to form on saidviewing screen an enlarged focused reproduction of an image in saiddisplay position, said first means having a cover glass plate of precisethickness disposed over and in contact with said transparency, ananti-reflection coating on said glass plate on the side opposite fromsaid transparency, and means for resiliently urging said projection lensassembly against the anti-reflection coating on said glass plate for allimage display positions, the portions of said projection lens assemblycontacting said anti-reflection coating being provided with alubricating film, whereby said lens assembly is maintained at a precisedistance from said transparency for all image display positions thereofand whereby said second means can position said first means withoutlifting said projection lens assembly from contact with said glassplate.

9. The invention in accordance with claim 8, wherein said projectionlens is of the microscope-type providing a magnification of to 1 orgreater and having a working distance of 20 millimeters or less.

10. The invention in accordance with claim 8, wherein said first meansincludes means for pivotably mounting said glass plate, and wherein saidsecond means is constructed and arranged to permit said first means tobe moved to a position such that the urging of said projection lensassembly thereagainst causes pivoting of said glass plate, whereby atransparency can be inserted or removed without raising said projectionlens assembly from contact with said first means.

11. The invention in accordance with claim 8, wherein said projectionlens assembly includes a fixed portion, a movable portion movable in adirection towards said cover glass plate, means for mounting saidprojection lens for movement along with said movable portion, and aspring interposed between said fixed and movable portions for urgingsaid movable portion into resilient contact with said cover glass plate,said movable portion also including an adjustable member for adjustingthe spacing between said projection lens and the surfaces of saidmovable portion which contact said glass cover plate.

12. The invention in accordance with claim 8, wherein said displayapparatus is of the rear projection type, said means cooperating withsaid projection lens being constructed and arranged to project saidenlarged image on the opposite side of said viewing screen from whichsaid viewing screen is viewed.

13. The invention in accordance with claim 8, wherein said displayapparatus is provided with a horizontal base member below saidprojection lens assembly, and wherein said first and second means areconstructed and arranged for cooperative engagement and slidablemovement on said base member such that said second means is restrictedto slidable movement in only a first direction with respect to saidprojection lens assembly while said first means is caused to movetogether with said second means during movement in said first directionand is also movable with respect to said second means in a directionperpendicular to said first direction, whereby x-y movement of atransparency retained in said first means is provided.

14. The invention in accordance with claim 13, wherein said first meansincludes a lower glass plate cooperating with said cover glass plate soas to retain a transparency therebetween.

References Cited UNITED STATES PATENTS 1,894,005 1/1933 Rose 88-243,224,326 12/ 1965 Brownscombe 88--24 3,267,801 8/1966 Abbott et a1.88-24 3,352,201 11/1967 Brownscombe 8824 NORTON ANSHER, PrimaryExaminer. RICHARD M. SHEER, Assistant Examiner.

US. Cl. X.R.

1. IN APPARATUS FOR DISPLAYING A REDUCED IMAGE RECORDED ON ATRANSPARENCY, A PROJECTION LENS ASSEMBLY, A LIGHT SOURCE, RETAININGMEANS FOR RETAINING A TRANSPARENCY BETWEEN SAID PROJECTION LENS ASSEMBLYAND SAID LIGHT SOURCE, SAID RETAINING MEANS INCLUDING A PIVOTABLE MEMBERDISPOSED OVER AND IN CONTACT WITH THE TRANSPARENCY ON THE PROJECTIONLENS ASSEMBLY SIDE THEREOF, MEANS FOR URGING SAID PROJECTION LENSASSEMBLY AGAINST SAID PIVOTABLE MEMBER, AND MEANS FOR MOVING SAIDRETAINING MEANS TO A POSITION SO THAT THE URGING OF SAID PROJECTION LENSASSEMBLY AGAINST SAID PIVOTABLE MEMBER CAUSES PIVOTING THEREOF, WHEREBYA TRANSPARENCY CAN BE INSERTED OR REMOVED.